void main(List<String> args) {
  //1.while循环
  int a = 0;
  while (a < 10) {
    print(a);
    a++;
  }
  //2.do...while循环
  do {
    print(a);
    a++;
  } while (a < 10);
  //3.for循环
  for (int i = 0; i < 10; i++) {
    print(i);
  }
  //4.break语句
  for (int i = 0; i < 10; i++) {
    if (i == 5) {
      break;
    }
    print(i);
  }
  //5.continue语句：跳出当前循环，进入下一个循环
  for (int i = 0; i < 10; i++) {
    if (i == 5) {
      continue;
    }
    print(i);
  }
}
